CBT reduces CBF: cognitive‐behavioral therapy reduces cerebral blood flow in fear‐relevant brain regions in spider phobia

BACKGROUND: Imaging studies have provided evidence that cognitive‐behavioral therapy (CBT) is able to change brain activation in phobic patients in response to threatening stimuli. The changes occurred in both emotion‐generating and modulatory regions. In this study, we use a data‐driven approach to explore resting state cerebral blood flow (CBF) measured by arterial spin labeling (ASL), before and after CBT. METHODS: Eight female patients with spider phobia were scanned before and 1 month after an exposure‐based group therapy for spider phobia. Each MRI session consisted of an ASL resting state measurement acquired before and after a symptom provocation task involving the showing of spider pictures in the scanner. The first ASL acquisition measured anticipatory anxiety and the second measured postprocessing of phobia‐relevant stimuli. RESULTS: Cognitive‐behavioral therapy significantly reduced spider phobic symptoms in all patients. Symptom reduction during anticipatory anxiety was accompanied by reduced bilateral CBF in the parahippocampal gyrus, ventral anterior thalamus, Brodmann area 8, and the anterior cingulate cortex. During postprocessing of phobia‐relevant stimuli, patients showed reduced CBF in the bilateral insula, components of the motor cortex, and areas associated with language functions. CONCLUSIONS: Longitudinal CBF dynamics following CBT were in concordance with results from several studies using BOLD fMRI to investigate the effects of psychotherapy on brain activity. CBF can be quantified by ASL, with the principal advantage of sensitivity to slow variations in neural activity and task independence. Therefore, ASL may be a suitable method for monitoring and evaluating the efficacy of psychotherapy or pharmacotherapy approaches.